Karl Friston

Published online at Scientific American on March 19, 2018. It was midday when an ambulance brought Rose to the Emergency Department. The triage nurses, with their characteristic knack for brevity, had written “50 year old schizophrenic woman hearing/seeing dead boyfriend.” The medical team had done the standard workup—temperature, blood pressure, EKG, labs to screen for an electrolyte imbalance, drug or...